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Activation and induction of cytosolic phospholipase A 2 by TNF‐α mediated through Nox2, MAPKs, NF‐κB, and p300 in human tracheal smooth muscle cells
Author(s) -
Lee ChiangWen,
Lin ChihChung,
Lee ITa,
Lee HuiChun,
Yang ChuenMao
Publication year - 2011
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.22537
Subject(s) - p38 mitogen activated protein kinases , nadph oxidase , apocynin , microbiology and biotechnology , kinase , phospholipase a2 , tumor necrosis factor alpha , transfection , mapk/erk pathway , chemistry , protein kinase a , biology , biochemistry , reactive oxygen species , immunology , enzyme , gene
Cytosolic phospholipase A 2 (cPLA 2 ) plays a pivotal role in mediating agonist‐induced arachidonic acid (AA) release for prostaglandin (PG) synthesis during inflammation triggered by tumor necrosis factor‐α (TNF‐α). However, the mechanisms underlying TNF‐α‐induced cPLA 2 expression and PGE 2 synthesis in human tracheal smooth muscle cells (HTSMCs) remain unknown. Here, we report that TNF‐α‐induced cPLA 2 protein and mRNA expression, PGE 2 production, and phosphorylation of p42/p44 MAPK, p38 MAPK, and JNK1/2, which were attenuated by pretreatment with a ROS scavenger [ N ‐acetyl‐ L ‐cysteine, (NAC)] and the inhibitors of NADPH oxidase [apocynin (APO) and diphenyleneiodonium chloride (DPI)], MEK1/2 (U0126), p38 MAPK (SB202190), and JNK1/2 (SP600125) or transfection with siRNA of Nox2, p47 phox , MEK1, p42, p38, or JNK2. TNF‐α‐induced cPLA 2 expression was also inhibited by pretreatment with a selective NF‐κB inhibitor [helenalin (HLN)] or transfection with dominant negative mutants of NF‐κB inducing kinase (NIK) or IκB kinase (IKK)α/β. TNF‐α‐induced NF‐κB translocation was blocked by pretreatment with NAC, DPI, APO, or HLN, but not by U0126, SB202190, or SP600125. In addition, pretreatment with curcumin (a p300 inhibitor) or transfection with p300 siRNA blocked cPLA 2 expression and PGE 2 synthesis induced by TNF‐α. We further confirmed that p300 was associated with the cPLA 2 promoter which was dynamically linked to histone H4 acetylation stimulated by TNF‐α, determined by chromatin immunoprecipitation assay. Association of p300 and histone H4 to cPLA 2 promoter was inhibited by U0126, SB202190, and SP600125. These results suggested that in HTSMCs, activation of p47 phox , MAPKs, NF‐κB, and p300 is essential for TNF‐α‐induced cPLA 2 expression and PGE 2 release. J. Cell. Physiol. 226: 2103–2114, 2011. © 2010 Wiley‐Liss, Inc.